Grimmia longirostris |
Grimmia mariniana |
|
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grimmia dry rock moss |
grimmia dry rock moss |
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Habit | Plants in compact cushions, yellow-green to dark olivaceous. | Plants in hoary loose cushions, emerald green to black. |
Stems | 1–3 cm, central strand strong. |
0.6–1.2 cm, central strand weak. |
Leaves | ovate-lanceolate, 1.5–3 × 0.6–0.7 mm, keeled, one margin recurved proximally, not sheathing, awn 0.5–1.5 mm, costal transverse section prominent, reniform; basal juxtacostal laminal cells long-rectangular to linear, sinuose, thick-walled; basal marginal laminal cells short-rectangular, straight, with thick transverse and thin lateral walls, hyaline; medial laminal cells short-rectangular, sinuose, thick-walled; distal laminal cells 2-stratose, not bulging, marginal cells 2-stratose, not bulging. |
linear-lanceolate to narrowly ovate-lanceolate, 1.5–2.1 × 0.5–0.7 mm, keeled, not plicate, margins incurved distally, awn 0.4–0.8 mm, costal transverse section prominent, semicircular; basal juxtacostal laminal cells short-rectangular to elongate, sinuose, thick-walled; basal marginal laminal cells quadrate to short-rectangular, straight, thick-walled, hyaline; medial laminal cells quadrate, sinuose, thick-walled; distal laminal cells 2-stratose, not bulging, marginal cells 2-stratose, not bulging. |
Seta | straight, (1–)2–4 mm. |
straight, to 1 mm. |
Sexual condition | cladautoicous, perichaetial leaves not enlarged. |
dioicous, perichaetial leaves slightly enlarged. |
Capsule | usually present, (emergent to) exserted, yellow, oblong-ovoid to cylindric, exothecial cells short- to long-rectangular, thin-walled, stomata present in 2–3 rows, annulus of 2 rows of rectangular, thick-walled cells, operculum long-rostrate, peristome present, fully-developed, split and perforate in distal half. |
occasionally present, immersed to emergent, yellow (rarely brown), ovoid with an open mouth, faintly but distinctly ribbed, exothecial cells rectangular, thick-walled, stomata absent, annulus of 1 row of quadrate, thick-walled cells, operculum rostellate, with a short obtuse beak, peristome present, but rudimentary, teeth composed of only a few basal cells, sometimes perforated. |
Grimmia longirostris |
Grimmia mariniana |
|
Habitat | Exposed, dry, acidic granite and quartzite | Acidic sedimentary and basaltic metavolcanics |
Elevation | low to high eleavations (100-3100 m) [low to high eleavations (300-10200 ft)] | moderate elevations 900-1200 m [moderate elevations 3000-3900 ft] |
Distribution |
AK; AZ; CA; CO; ID; ME; MN; MT; NC; NH; NM; NV; OK; OR; SD; TX; UT; VT; WA; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; QC; SK; YT; Mexico; South America; Africa; Pacific Islands; Greenland; Eurasia; Central America (Costa Rica, Guatemala, Honduras); Australia
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CA |
Discussion | Grimmia longirostris is one of the most common species of the genus. It is most common in the eastern ranges of the Rocky Mountains, ranging from western Texas through the Canadian Rockies, and throughout much of Alaska. It is widely distributed in the Canadian sub-Arctic and Arctic, and is known from Greenland. With the exception of disjunct sites in Oklahoma and North Carolina, it is absent in the American Great Plains and Southeast. These latter areas are largely composed of calcareous rocks, a substrate avoided by G. longirostris. It is rare in coastal areas, becoming more common inland. As Grimmia affinis, G. longirostris has commonly been placed as a subspecies of G. ovalis. Despite G. Sayre’s (1951) resolution of the differences between these taxa, a large proportion of specimens in major herbaria in North America that are named G. ovalis are actually G. longirostris. However, G. ovalis is dioicous and has leaves with plane margins that are broadly concave distally, usually with a distinct ovate base and well-defined shoulders. In contrast, G. longirostris is autoicous, and has leaves with one recurved margin, that are narrowly keeled distally, with a poorly defined basal region, often without a distinct shoulder. These characters clearly separate these two taxa at the specific level. Hastings puts G. longirostris into a group that also includes G. arizonae and G. pilifera. Grimmia longirostris is separated from those two species by non-sheathing leaf bases, usually long-exserted capsules, and cladautiocous sexuality. Grimmia longirostris is further separated from G. pilifera by having a stem with a distinct central strand and a thin epidermis, a costal transverse section that is typically reniform, and leaves that are recurved on only one margin. Rare specimens of G. longirostris with immersed capsules in the American Southwest may be almost indistinguishable from G. arizonae. In extremely xeric environments, specimens become friable and break into individual strands, making determination of the cladautiocous sexuality impossible. In these circumstances identification will always be uncertain. However, the leaves of G. longirostris are not sheathing; they are only loosely attached to the stem and usually can be peeled off intact. In contrast, the leaves of G. arizonae are sheathing and strongly attached to the stem; they often break at the base when trying to remove them. The costal transverse sections of G. longirostris are characteristically reniform (J. Muñoz 1998) while those of G. arizonae are usually semicircular. However, gradations from semicircular to reniform are not uncommon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Grimmia mariniana is known only from the coastal mountains of central California. If fertile, the immersed capsules with rudimentary peristome teeth will separate it from both G. montana and G. alpestris, which, while also being dioicous and without stomata, have long-exserted capsules with fully-developed peristome teeth. Grimmia nevadensis is similar but lacks peristome teeth, has uniformly rectangular, thin-walled basal laminal cells, and does not have hyaline margins. The faint ribs on the capsules of G. mariniana may not be evident when the capsules are not turgid. Sterile specimens can be separated from G. alpestris by the lack of bulging cells, and the narrow leaves. Distinguishing sterile specimens of G. mariniana from G. montana is more problematic, as both have narrowly ovate-lanceolate leaves, with similar areolation. However, the basal marginal laminal cells of G. mariniana are hyaline while those of G. montana are not. Grimmia mariniana is easily separated from G. arizonae and G. pilifera, two other members of the subgenus, along with G. nevadensis, that have immersed capsules. Sporophytically, both G. arizonae and G. pilifera have abundant stomata, well-developed peristome teeth, and rectangular, thick-walled, multi-layered annuli. Gametophytically, the incurved leaf margins of G. mariniana contrast sharply with the recurved leaf margins of G. arizonae and G. pilifera. Sayre noted the similarity of G. mariniana to G. anodon. The straight, centrally attached seta and symmetric capsule usually with rudimentary peristome teeth will serve to separate specimens of G. mariniana from G. anodon. Gametophytically, the long, narrow leaves, with incurved margins and 2-stratose distal laminal cells separates G. mariniana from G. anodon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 27, p. 239. | FNA vol. 27, p. 234. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | G. affinis, G. arctophila subsp. labradorica, G. catalinensis, G. catalinensis var. mutica, G. elata, G. ortholoma, G. ovalis var. affinis, G. ovata var. affinis, G. ovateoformis | |
Name authority | Hooker: Musci Exot. 1: plate 62. (1818) | Sayre: Bryologist 58: 323. (1955) |
Web links |